1. Field of the Invention
The present invention relates to an apparatus with an improved photodetector circuit activated by colored translucent objects and which provides highly selective detection between objects of different color, hue, reflectance and light absorbance. The present invention particularly relates to an apparatus containing a circuit which detects a gravity fed moving colored translucent disc as the object which is inserted into the inside of a closed housing.
In the present invention, detection of a genuine object or token requires that at least two monochromatic light source/photodetector pairs, when simultaneously sensing light transmitted through the translucent token, produce a voltage within their respective comparator circuits which is within a very narrow present range such that desired comparator output voltages are produced. If and when all comparators reach the desired output voltages simultaneously, an AND gate means produces a "high" output voltage which actuates a timer means and an on-off switch means which controls the activation and time period to deactivation of any electrical appliance, device, apparatus, machine or process connected to the on-off means.
Objects (tokens) having a very wide range of color, hue, reflectivity, light absorbance and combinations thereof can be accurately and reliably detected by this apparatus. Moreover, the apparatus is very easily adjusted to detect objects (tokens) of widely varying color, hue, reflectivity, absorbance and combinations thereof by simply adjusting potentiometers determining comparator integrated circuit reference voltages. Objects of varying physical size and shape can be accommodated for detection by altering the token pathway within the apparatus to an appropriate size and shape.
A method of using the apparatus is also described. The apparatus and method are particularly useful for controlling activation and deactivation of appliances, devices, machines or processes connected thereto by means of genuine objects (tokens) given to potential users as a reward for desired services or behavior.
2. Prior Art
The prior art has generally described the use of photocells in a variety of detection apparatus. Illustrative are U.S. Pat. Nos. 2,016,036; 2,131,091; 2,237,132; 3,807,875; 3,012,666; 3,473,036; 3,541,339; 3,921,003; 4,015,121; 4,075,507; 4,082,188; 4,089,400; 4,136,961; and 4,172,222. In many of these devices, the position of specific patterns or features of coins or other objects was detected by means of light passing by, reflected from or transmitted through the object being interrogated. None of these devices, however, appear to have provided reliable and precise detection of transmitted light through a selected moving colored translucent object.
Prior art also described various apparatus including photoelectric comparator circuits which detect color and/or position of specific patterns or features by means of light transmitted through and/or reflected from a genuine bank note or other translucent object in order to determine authenticity. Illustrative are U.S. Pat. Nos. 3,480,785; 3,491,234; 3,496,370; 3,497,304 and 3,679,314. Such photodetector circuits do not accurately and reliably detect the genuineness of a selected, moving colored, translucent object; nor are they easily adjustable to detect selected moving translucent objects having a wide variety of optical characteristics such as variations in color, hue, reflectance and light absorbance. There was a need, therefore, to provide an improved photodetector circuit which would accurately and reliably detect the genuineness of a selected moving translucent object; and also which would be easily adjustable so that genuine translucent objects having a wide range of colors, hue, reflectance and light absorbancy could be accurately and reliably detected.